This invention relates to a vehicle steering control apparatus for following a riderless vehicle along a reference path provided on a floor, a ground, or other flfat plates.
Riderless vehicles steering control apparatus have been employed for correcting vehicle steering to align the riderless vehicle suficient well over prescribed reference paths defined by guide tapes by the aid of an optical sensor assembly operable to measure momentary deviations of the riderless vehicle from the reference path. The optical sensor assembly includes a plurality of sensor units arranged on a line, each sensor unit including a downward-facing light emission diode operable to emeit a light ray and a downward-facing photodiode sensitive to the light ray reflected from the floor or the guide tape. With such conventional apparatus, however, it is necessary to avoid light interference by arranging one sensor unit out of the reflected light area resulting from a light ray emitted from another sensor unit. This has been the primary limitation on optical sensor assemblies, and as a result, fine and accurate deviation measurements have not been reliably obtainable in conventional riderless vehicle steering control apparatus. This has been a serious problem particularly for applications to high-speed riderless vehicles.